On 01/19/18 at 12:45pm, Petr Tesarik wrote:
> The crashed reserved memory end offset is the last address within
> range, whereas the end offset in the pt_loads[] denotes the first
> address past the range. This has caused a number of off-by-one
> errors in exclude_segment().
>
> First, let's unify the meaning of "end" to be the first out-of-range
> address, i.e. start + size. Thanks to that, no +1 or -1 adjustments
> are needed in exclude_segment().
>
> Second, since the value read from /proc/iomem is the last address
> within range, add one when passing it as an argument to
> exclude_segment(). This is now the only adjustment by one.
>
> Signed-off-by: Petr Tesarik <ptesarik@xxxxxxxx>
> ---
> elf_info.c | 18 +++++++++---------
> 1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/elf_info.c b/elf_info.c
> index 69b1719..1eaddd9 100644
> --- a/elf_info.c
> +++ b/elf_info.c
> @@ -820,26 +820,26 @@ static int exclude_segment(struct pt_load_segment **pt_loads,
> if (kvstart < vend && kvend > vstart) {
> if (kvstart != vstart && kvend != vend) {
> /* Split load segment */
> - temp_seg.phys_start = end + 1;
> + temp_seg.phys_start = end;
> temp_seg.phys_end = (*pt_loads)[i].phys_end;
> - temp_seg.virt_start = kvend + 1;
> + temp_seg.virt_start = kvend;
Does the old code cause error? I remember I thought about this, forget
why I still took the old way.
Looks a good clean up.
> temp_seg.virt_end = vend;
> temp_seg.file_offset = (*pt_loads)[i].file_offset
> + temp_seg.virt_start - (*pt_loads)[i].virt_start;
> temp_seg.file_size = temp_seg.phys_end
> - temp_seg.phys_start;
>
> - (*pt_loads)[i].virt_end = kvstart - 1;
> - (*pt_loads)[i].phys_end = start - 1;
> + (*pt_loads)[i].virt_end = kvstart;
> + (*pt_loads)[i].phys_end = start;
> (*pt_loads)[i].file_size -= temp_seg.file_size;
>
> tidx = i+1;
> } else if (kvstart != vstart) {
> - (*pt_loads)[i].phys_end = start - 1;
> - (*pt_loads)[i].virt_end = kvstart - 1;
> + (*pt_loads)[i].phys_end = start;
> + (*pt_loads)[i].virt_end = kvstart;
> } else {
> - (*pt_loads)[i].phys_start = end + 1;
> - (*pt_loads)[i].virt_start = kvend + 1;
> + (*pt_loads)[i].phys_start = end;
> + (*pt_loads)[i].virt_start = kvend;
> }
> (*pt_loads)[i].file_size -= (end -start);
> }
> @@ -917,7 +917,7 @@ int get_kcore_dump_loads(void)
>
> for (i = 0; i < crash_reserved_mem_nr; i++) {
> exclude_segment(&pt_loads, &num_pt_loads,
> - crash_reserved_mem[i].start, crash_reserved_mem[i].end);
> + crash_reserved_mem[i].start, crash_reserved_mem[i].end + 1);
> }
>
> max_file_offset = 0;
> --
> 2.13.6
>
>
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